Solvent-based Processes Research Articles

Dimethyl Ether as a Novel Solvent for Bitumen Recovery: Mechanisms of Improved Mass Transfer and Energy Efficiency

Summary A solvent-based thermal recovery process has the advantages of low capital expenditure, less energy consumption, and less greenhouse gas emission. Dimethyl ether (DME), as a renewable solvent, has been considered as a novel additive in the thermal bitumen recovery process. Being soluble in both water and oil phases, DME has the potential to enhance mass transfer and improve oil production. In this work, a phase behavior model of the DME-bitumen-water system is first developed considering DME partitioning between oil and water. A field-scale numerical simulation model with fine gridblocks is developed to investigate the heat and mass transfer mechanisms between DME and bitumen in the interface of a DME vapor chamber. The numerical model is validated with physical experiment results. The close agreement between measured and simulated production profiles indicates that the mechanisms are adequately captured. Meanwhile, various simulation scenarios are performed to evaluate the production performance and the energy efficiency, which is defined as the energy/oil ratio. It is found that the oil production rate in DME injection is 15% higher than that in butane injection at the early stage of production. The solvent penetration depth in DME injection is larger than that in butane injection. This is attributed to the enhanced mass transfer between DME and bitumen caused by the high diffusion of DME in the water phase and preferential partitioning of DME into the oil phase. Furthermore, energy consumption in the warm DME injection process is 48% less than that in warm butane injection and 75% less than that in steam-assisted gravity drainage (SAGD). This is because DME injection can be operated at a lower-temperature condition, leading to less energy transferred to heat reservoir rock/fluids and less heat loss to over/underburden. Therefore, DME is proved to be a technically promising and environmentally friendly solvent to enhance bitumen recovery. The DME-based thermal recovery technique exhibits superior advantages in unlocking poor-quality reservoirs, especially in high water saturation reservoirs and thin reservoirs.

Comparison of Aging Resistance and Antimicrobial Properties of Ethylene-Norbornene Copolymer and Poly(Lactic Acid) Impregnated with Phytochemicals Embodied in Thyme (Thymus vulgaris) and Clove (Syzygium aromaticum).

The effects of plant-based extracts on the solar aging and antimicrobial properties of impregnated ethylene–norbornene (EN) copolymer and poly(lactic acid) (PLA) were investigated. In this study, the impregnation yield of polyolefin, lacking in active centers capable of phytochemical bonding, and polyester, abundant in active sides, was measured. Moreover, two different extracts plentiful in phytochemicals—thyme (TE) and clove (CE)—were employed in the solvent-based impregnation process. The effect of thymol and eugenol, the two main compounds embodied in the extracts, was studied as well. Interestingly, oxidation induction times (OIT) for the impregnation of EN with thyme and clove extracts were established to be, respectively, 27.7 and 39.02 min, which are higher than for thymol (18.4 min) and eugenol (21.1 min). Therefore, an aging experiment, mimicking the full spectrum of sunlight, was carried out to investigate the resistance to common radiation of materials impregnated with antioxidative substances. As expected, the experiment revealed that the natural extracts increased the shelf-life of the polymer matrix by inhibiting the degradation processes. The aging resistance was assessed based on detected changes in the materials’ behavior and structure that were examined with Fourier-transform infrared spectroscopy, contact angle measurements, color quantification, tensile tests, and hardness investigation. Such broad results of solar aging regarding materials impregnated with thyme and clove extracts have not been reported to date. Moreover, CE was found to be the most effective modifying agent for enabling material with antimicrobial activity against Escherichia coli to be obtained.

Kinetic modelling of the solid\u2013liquid extraction process of polyphenolic compounds from apple pomace: influence of solvent composition and temperature

This study aims to assess kinetic modelling of the solid–liquid extraction process of total polyphenolic compounds (TPC) from apple pomace (AP). In this regard, we investigated the effects of temperature and solvent (i.e. water, ethanol, and acetone) on TPC extraction over various periods. The highest TPC yield of 11.1 ± 0.49 mg gallic acid equivalent (GAE)/g db (dry basis) was achieved with a mixture of 65% acetone–35% water (v/v) at 60 °C. The kinetics of the solvent-based TPC extraction processes were assessed via first-order and second-order kinetic models, with an associated investigation of the kinetic parameters and rate constants, saturation concentrations, and activation energies. The second-order kinetic model was sufficient to describe the extraction mechanism of TPC from AP. This study provides an understanding of the mass transfer mechanism involved in the polyphenolic compound extraction process, thus facilitating future large-scale design, optimization, and process control to valorize pomace waste.Graphical

(Invited) Enabling Direct Recycling of Lithium-ion Batteries via Solvent-based Electrode Recovery

Lithium-ion batteries (LIBs) are revolutionizing electric vehicles as they have done the same to portable electronics. Production of LIBs are ramping up dramatically with the widely emerging of gigafactories globally, so are the manufacturing scraps and end-of-life batteries, thereby urging the development of cost-effective and environmentally sustainable recycling technologies to manage those waste. Currently, the recycling of LIBs is still at early stage, with many technical constraints to overcome. Direct recovery of electrode materials (e.g., LiCoO2, NCA, NMC, graphite) from manufacturing scraps as well as spent cells with useful morphology and comparable electrochemical performance could substantially reduce the battery costs and mitigate both energy and environmental impacts. However, electrode materials are tightly bonded to their current collectors by organic binders like PVDF, making them hard to be separated. In this context, we aim to advance direct recycling of LIBs from different aspects through solvent-based recovery processes. The solvent-based separation processes developed here have enabled low-temperature and highly efficient recovery of electrode materials without any morphological damages or introduction of impurities. The recovered electrode materials from manufacturing scraps are reprocessed as new electrode with similar electrochemical performance for a new loop of battery manufacturing. Furthermore, metal foils like copper and aluminum are fully recovered without any corrosion, greatly expanding the recycling revenues. We believe that our solvent-based electrode recovery processes pave the way for direct recycling of LIBs.

Recent Advances in the Catalytic Treatment of Volatile Organic Compounds: A Review Based on the Mixture Effect

Catalytic total oxidation is an efficient technique for treating VOCs, which are mainly emitted by solvent-based industrial processes. However, studies of the catalytic oxidation of VOCs in combination with other pollutants are very limited, despite the fact that this is a key step of knowledge before industrial application. During the oxidation reaction, the behavior of a molecule may change depending on the reaction mixture. For the treatment of an effluent loaded with VOCs, it is necessary to carefully select not only the catalytic material to be used but also the reaction conditions. Indeed, the catalytic oxidation of a component in a VOCs mixture is not predicted solely from the behavior of individual component. Thus, the objective of this small review is to carry out a study on the effect observed in the case of the oxidation of a VOCs mixture or in the presence of water, NOX or sulfur compounds.

Incorporating phase behavior constraints in the multi-objective optimization of a warm vaporized solvent injection process

The warm vaporized solvent injection process has been proposed as a more environmentally friendly alternative to steam-based technologies for bitumen recovery. The process typically involves injecting heated solvent vapor into a horizontal injector; the solvent condenses and dissolves into bitumen, while the diluted oleic phase would flow towards a horizontal producer. Despite the promising results reported from several pilot projects near Fort McKay, Alberta, successful commercial-scale extraction is costly and would require a detailed optimization of the pertinent design variables. The main challenge is that this is a multi-objective optimization (MOO) problem, which aims to balance the trade-offs between conflicting performance objectives while honoring the various operational constraints. In this study, a systematic workflow is formulated to optimize these multiple conflicting performance objectives considering phase behavior constraints. A 2D synthetic model based on typical Athabasca oil sands properties is constructed to simulate the warm vaporized solvent process. The addition of non-condensable gas (methane) into the solvent (propane) is examined. The resultant changes in thermodynamic properties and equilibrium phase behavior are considered in determining the practical limits of the decision variables (e.g., bottom-hole injection pressure and temperature). The objective functions, including oil recovery factor, solvent retained-to-oil ratio, and energy consumption, are defined, and a factorial experimental design is employed to identify a subset of decision variables that exhibit minimal redundancy internally and create the dataset for proxy model development. To reduce the computational costs associated with reservoir simulations, proxy models, e.g., the artificial neural network (ANN), is developed and applied. Finally, a Pareto-based MOO scheme is implemented to estimate the optimal decision variables. Despite the higher front-end loading requirement of the ANN proxy modeling, the MOO with proxy modeling still requires significantly less execution/running time as compared to a MOO with traditional flow simulation (e.g., a 97% reduction in CPU time). This reduced running time is important for alleviating the computational load when evaluating the objective functions during the optimization process. More importantly, this optimization scheme is capable of identifying a set of optimal decision variables. This work presents a practical workflow for optimizing various design variables associated with many solvent-based bitumen recovery processes. Specific considerations including the practical limits for operating constraints and computational efficiency are examined and incorporated. It is anticipated that this workflow can be readily integrated into the design and decision-making processes in reservoir management.

Validation of a solvent-based process for the smoothing of additively manufactured 3D models of nasal cavities

Abstract In order to improve the reliability of diagnosis of nasal breathing disorders, aerodynamic properties have to be analyzed through experiments based on 3D models. The surface properties of the prepared respective 3D models using fused deposition modeling (FDM) should match those of native nasal cavities, thus representing their normal state and typical pathologies. In this work, we validated the smoothing of dual extruded 3D printed samples of PLA (polylactide) and PVA (polyvinyl alcohol) using the solvent TFE (trifluoroethanol). The smoothing was conducted in vapour and liquid phases of TFE. Before and after treatment of the samples in liquid and vapour phases of TFE, mass and surface roughness analysis were performed. The results of this work will help to produce and process a representative model of the human paranasal sinuses, which can be created using CT data from a patient.

Construction of a Novel Substrate of Unfigured Islands-in-Sea Microfiber Synthetic Leather Based on Waste Collagen.

This study is to introduce waste collagen into an unfigured islands-in-sea microfiber nonwoven material, replacing the polyurethane impregnation section of the traditional manufacturing process with the collagen impregnation process. The modified collagen was first impregnated in polyamide/low-density polyethylene (PA/LDPE) fiber nonwoven to form a film. Then the low-density polyethylene component was extracted and dissolved in toluene, resulting in a collagen-based microfiber nonwoven substrate. Waste collagen was first modified to introduce C=C into the molecular chain to obtain vinyl collagen (CMA), and then the following film formation conditions for CMA were studied: 73% degree of substitution (DS), 3 h cross-linking time, and 0.005–0.01 wt % initiator concentration. Then, the preparation of CMA-PA/LDPE and toluene extraction processes were investigated. The optimum toluene extraction conditions were obtained as an extraction temperature of 85 °C and an extraction time of 110 min. The properties of the nonwoven materials were compared before (CMA-PA/LDPE) and after (PA-CMA) extraction. It was found that the homogeneity, tensile strength, and static moisture permeability of the PA-CMA materials prepared by CMA with 50 and 73% DS were all superior to those of PA/LDPE. In particular, the static moisture permeability of PA-CMA (691.6 mg/10 cm2·24 h) increased by 36.2% compared to the microfiber synthetic leather substrate currently in the market. Using scanning electron microscopy (SEM), the continuity of a film of PA-CMA with 73% DS was observed to be better and the fibers were differentiated and relatively tighter fiber-to-fiber gap. The studied novel green process can eliminate the large amount of dimethylformamide (DMF) pollution caused by the current solvent-based polyurethane impregnation process.

Business Roundup

BUSINESS Business Roundup ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2021, 99 (34), p 19September 20, 2021Cite this:C&EN 99, 34, 19AbstractMitsui & Co. has signed an agreement to develop a polypropylene recycling plant in Japan that will use PureCycle Technologies’ solvent-based purification process. PureCycle recently signed a similar agreement with SK Geo Centric for a plant in South Korea. Lycia Therapeutics has raised $70 million in series B financing to develop lysosomal targeting chimeras, or LYTACS, to promote the degradation of disease-causing proteins. The funding comes shortly after an agreement between Lycia and Eli Lilly and Company to develop LYTACS. Calysta , a producer of high-protein fish food made by feeding single-cell microbes with natural gas, has raised $39 million in series D funding, including $10 million from BP’s investment arm. Calysta will use the cash to build its second manufacturing plant. Mitsui Chemicals has agreed to acquire the agrochemical business of Japan’s Meiji Seika Pharma for an undisclosed sum. The business employs about 110 people and develops specialty pesticides,View: PDF | Full Text HTML

A Novel Dual-Stage Phase Separation Process for CO2 Absorption into a Biphasic Solvent with Low Energy Penalty.

An amine-based biphasic solvent is promising to cut down the energy penalty of CO2 capture. However, the high viscosity of the CO2-enriched solvent retards its industrial application. This work proposed a novel dual-stage phase separation process using a triethylenetetramine and 2-(diethylamino)ethanol blend as a biphasic solvent, which separates a certain proportion of CO2-enriched phase during CO2 absorption to reduce its viscosity. Experimental results showed that the proposed dual-stage phase separation process improved the phase separation behavior and effectively enhanced the absorption rate by 49% at 50 °C, when 50 vol % CO2-enriched phase was separated at 0.3 mol mol-1. Kinetic analysis showed that the absorption rate was mainly controlled by liquid-side mass transfer. The regeneration heat of the dual-stage phase separation process cut down the energy penalty by 33% compared with the monoethanolamine-based process. Compared with the conventional biphasic solvent-based process, the heat duty was further declined by 8%. The 1H nuclear magnetic resonance analysis showed that the dual-stage phase separation process could effectively control the generation of absorption products and intensify the interphase migration of tertiary amines.

A new GPC/TREF/LinELSD instrument to determine the molecular weight distribution and chemical composition: application to recycled polymers

The linearized evaporative light scattering detector (LinELSD) incorporates an inverse power function facilitating the characterization of polymers in solution. To show the benefits of the LinELSD, a versatile liquid chromatograph was built by combining a high temperature gel permeation chromatograph (HT-GPC), a fast cooling/heating oven of a gas chromatograph (GC), and the LinELSD. Apart from the main GPC functionality to measure the molecular weight distribution (MWD) of polymers, the injected samples can also be eluted as a function of polymer type by applying a temperature rising elution fractionation (TREF) program on the column placed in the GC oven. The hybrid GPC/TREF/LinELSD instrument removes the limitations of the commercial GPC and TREF systems manufactured with differential refractive index (DRI) or infrared (IR) detectors, which require a sensible difference between the refractive indices of polymer and solvent, or the absence of CH2 and CH3 groups in the solvent. Thus, the new instrument qualifies to characterize the chemical structure of recycled polymers, demanding more flexible analytical conditions than those previously developed for the virgin resin analysis. Moreover, the hybrid instrument allows to investigate polyolefin solutions in xylene and toluene, which are the preferred solvents for the selective extraction of high-performance polymers from mixed plastic waste, thus qualifying as a unique analytical solution to assess the emergent solvent-based purification industrial processes.

CO2 capture using ionic liquid-based hybrid solvents from experiment to process evaluation

The CO2 absorption capacity in three hybrid solvents based on butyl-3-methylimidazolium acetate ([Bmim][OAc]) and three different cosolvents (Dimethyl ethers of polyethylene glycol (DEPG250), propylene carbonate, and water) was investigated and compared, and [Bmim][OAc]-DEPG250 shows the highest CO2 absorption capacity. The effects of the mass ratio of [Bmim][OAc]-DEPG250 and temperature on their CO2 absorption capacity, density, and viscosity were further investigated. In addition, the absorption capacities of N2 and CO2 in [Bmim][OAc]-DEPG250 with the simulated flue gas as a feed gas were studied and compared with that using the pure gas as a feed gas. Thermodynamic models were used to represent the experimental data, and then process simulation and evaluation were carried out. The results show that the addition of DEPG250 dramatically decreases the viscosity, while the absorption capacity of hybrid solvents is still comparable with pure [Bmim][OAc]. The type of gas stream, that is, pure gas or gas mixture, has a negligible effect on the N2 and CO2 absorption capacity. The simulation results show that [Bmim][OAc]-DEPG250 only utilizes less than 50% of the heating duty of aqueous amine solution because of the low-pressure desorption and preheating with waste heat in this hybrid solvent-based process. The CO2 capture cost of using this [Bmim][OAc]-DEPG250 reduces by 11% compared with that of using aqueous amine solution due to the significant decrease (by 52%) in utility cost.

Numerical simulation of asphaltene deposition in porous media induced by solvent injection

We present numerical simulations of asphaltene deposition induced by solvent injection by the implementation of liquid-liquid equilibrium (LLE) data along with a reaction-based non-equilibrium mass transfer model. The interplay of viscous fingering and asphaltene deposition during the injection of dimethyl ether (DME) was studied. Our results reveal that one-dimensional approach fails to predict the real physics and underestimates the deposition. It is shown that DME injection leads to the upgrading of the produced oil. The results indicate that the dynamics of the viscous fingering are independent of the deposition rate and governed by the viscosity ratio. Our findings also suggest that grid dependency of deposition poses a computational challenge. To address this issue, we developed scaling relations to upscale the fine-scale deposition rate to the coarse-grid numerical simulations. This study finds application in solvent-based recovery processes and paves the way for integrating LLE data in numerical simulation of asphaltene deposition.

Towards estimating absorption of major air pollutant gasses in ionic liquids using soft computing methods

Capture of air pollutant gases using novel and green solvents is obtaining widespread attention. Accurate estimation of this process is complex. We have estimated the absorption of CO2, CH4, H2S, N2O, SO2 and CO gases in ionic liquids (ILs). We have applied Multilayer Perceptron-Artificial Neural Networks (MLP-ANN), Hybrid-Adaptive Neuro Fuzzy Inference System (Hybrid-ANFIS), Particle Swarm Optimization-Adaptive Neuro Fuzzy Inference System (PSO-ANFIS) and Coupled Simulated Annealing-Least Squares Support Vector Machine (CSA-LSSVM). We have gathered 3060 data of 72 IL-Gas mixtures for 40 types of ILs. The inputs of these models are: Temperature (T), pressure (P), IL molecular weight (MwIL), IL critical temperature (Tc, IL), IL critical pressure (Pc, IL), IL acentric factor (ωIL), gas molecular weight (Mwgas), gas critical temperature (Tc, gas), gas critical pressure (Pc, gas), gas kinetic diameter (d) and the acentric factor (ωgas). The CSA-LSSVM model produces best estimation with an Average Absolute Relative Deviation (AARD) of 8.7%. The results suggest the solubilities of the gases in ILs are correlated with structural factors of ILs. Estimation of the equilibrium behaviors in ionic liquids is of importance in simulation and design of solvent-based pollutant gas capture processes.

PureCycle to build big new plant

The plastics recycling firm PureCycle Technologies plans to spend $440 million to build a polypropylene recycling plant in Augusta, Georgia. The company uses a solvent-based process to purify postconsumer polypropylene waste for reuse. The firm went public through a merger with a special purpose acquisition company earlier this year. The new plant will have three processing lines, each with capacity of about 60,000 metric tons (t) per year. PureCycle is already building a plant with 50,000 t of annual capacity in Ironton, Ohio, which will start up in 2022. The company ultimately aims to have 450,000 t of output on the ground by 2025.

Statistical modelling and optimization of print quality and mechanical properties of customized tubular scaffolds fabricated using solvent-based extrusion 3D printing process.

Tissue-engineered tubular scaffolds offer huge potential to heal or replace the diseased organ parts like blood vessels, trachea, oesophagus and ureter. However, manufacturing these scaffolds in various scales and shapes is always challenging and requires progressive technology. Developing a flexible and accurate manufacturing method is a major developmental direction in the field of tubular scaffold fabrication. In this context, the present work presents a novel solvent-based extrusion 3D printing which allows extruding over a rotating mandrel to fabricate tubular scaffolds of polycaprolactone (PCL) and polyurethane (PU). Experimental runs were planned as per the central composite design (CCD) to evaluate the effects of input parameters like infill density, layer thickness, print speed and percentage of PU on the output responses like printing quality and mechanical characteristics. The printing quality was quantified by measuring average surface roughness of the printed scaffolds and mechanical properties were evaluated by measuring radial compressive load, and percentage of elongation. The experimental investigations revealed that printing quality was improved at higher infill densities and was deteriorated at higher print speeds and layer thicknesses. Similarly, the radial compressive load was improved with the increase in infill density and was decreased with an increase in layer thickness, print speed and percentage of PU. The percentage of elongation was found to improve at higher infill densities and percentages of PU and was reduced with an increase in layer thickness and print speed. Additionally, a multi-objective optimization using Genetic Algorithm was used to evaluate the optimum conditions to minimize surface roughness and maximizing radial compression load and percentage of elongation. Finally, a case study was performed by comparing the mechanical properties of tubular organs and scaffolds from the existing reports and results of the present work.

Production of a PET//LDPE Laminate Using a Reversibly Crosslinking Packaging Adhesive and Recycling in a Small-Scale Technical Plant

Multilayer packaging is an important part of the packaging market, but it is not recyclable with conventional methods since it is made of different thermodynamically immiscible materials. In this work, it was shown that it is possible to produce a PET//LDPE laminate in a pilot plant for lamination by using an adhesive consisting of maleimide- and furan-functionalized polyurethane prepolymers that cure through the Diels–Alder reaction. The material could then be delaminated in a small-scale recycling plant using a solvent-based recycling process by partially opening the Diels–Alder adducts through the influence of temperature. The PET and LDPE could be recovered without any adhesive residues before each material was regranulated, and in the case of the PE, a film was produced via cast film extrusion. The obtained PET granulate exhibited a slight, approximately 10%, decrease in molecular weight. However, since small amounts of LDPE could not be separated, compatibilization would still be required here for further use of the material. The obtained LDPE film was characterized by means of infrared spectrometry, differential scanning calorimetry, tensile testing, determination of the melt index, and molecular weight. The film showed lower crosslinking than usual for LDPE recycling and exhibited good mechanical properties. In this work, it was thus shown that upscaling of the laminate production with the modified adhesive and also its recycling at the pilot plant scale is possible and thus could be an actual option for recycling multilayer packaging.

Process intensification of CO2 capture by low-aqueous solvent

Low-energy solvent-based CO2 absorption processes have drawn attention as a next-generation post-combustion CO2 capture technology to reduce CO2 emissions from fossil fuel– or biomass-fired power generation and industrial flue gas streams. A low-aqueous (or water-lean) solvent process may substantially reduce the thermal energy consumption for solvent regeneration. Low-aqueous solvent–based processes are thermally sensitive, requiring a delicate temperature control within the absorber because of the fast exothermic amine-CO2 reaction and low heat capacity organic diluent. This reaction may result in heat accumulation in a packed absorption column and undesirable CO2 desorption occurring as the solvent moves through the column, reducing the solvent’s CO2 capture efficiency if its temperature is not controlled. Using a 3D printed intensified packing device, enhanced heat and mass transfer were demonstrated in an amine-CO2 scrubbing process using low-aqueous solvent. The multifunctional intensified device facilitates contact of the reactive solvent and gas phases in a single stage and heat removal by a cooling fluid flowing through channels in the interior of the corrugated plates of the device. These functionalities led to effective thermal management along the column via intrastage cooling and significant improvement in CO2 uptake under a wide range of operating conditions. Intrastage cooling effectively reduced the solvent average temperature along the column by ~10 °C and, as a result, the solvent’s capture efficiency improved by up to 25%.

Development of ultrathin polyamide nanofilm with enhanced inner-pore interconnectivity via graphene quantum dots-assembly intercalation for high-performance organic solvent nanofiltration

In this study, a high-performance organic solvent nanofiltration (OSN) membrane is engineered via nanoscale aminated graphene quantum dots (GQD_NH2)-mediated interfacial polymerization. The GQD_NH2, featuring favorable amine monomers, can atomically regulate the diffusion rate at the interface, yielding nanofilms with controllable thickness (decreasing from 200 to 100 nm). Furthermore, the zero-dimensional GQD_NH2 can serve as nanospacers to increase the inner-pore interconnectivity with loose internal architecture, while preserving the narrow free volume distribution via covalent interactions with the rubbery polymeric matrix. An improvement in solvent separation property is achieved, where the best-performing GQD_NH2@PA thin-film nanocomposite (TFN) membrane reaches a magnitude of 2.6-fold higher than that of the pristine polyamide (PA) membrane without significantly compromising its rejection toward organic solvation macro/micromolecules solutes, exhibiting high solvent permeances for mild solvents (such as 11.1 L m−2 h−1·bar−1 for methanol) and aggressive solvents (such as 5.9 L m−2 h−1·bar−1 for dimethylformamide), performing a competitive perm-selectivity among the state-of-the-art OSN membranes. The long-term operations (140 h) demonstrated the excellent stability of the nanocomposite membranes. We herein report the development of TFN membrane with thin and loose architecture for highly efficient organic solvent-based separation process.

Advanced configurations for post-combustion CO2 capture processes using an aqueous ammonia solution as absorbent

In this work, we have developed advanced process configurations for solvent-based CO2 capture processes that use aqueous ammonia as absorbent. In total, ten different advanced configuration concepts have been optimized and analysed, aiming at: (i) achieving in spec NH3 emissions in a controlled way; (ii) minimizing capital costs by avoiding redundant process components; (iii) minimizing the energy demand of the capture process by minimizing the requirements of high temperature steam and by maximizing the possibilities for the use of excess heat from the CO2 point source. As a result, we propose a new benchmark configuration for NH3-based capture processes that, with proper tuning of the process operating conditions, allows to minimize the specific energy consumption while enhancing the flexibility of the capture process with respect to the type and to the features of the electricity and steam available at the CO2 point source, at the minimum consumption of chemicals and process water. This new benchmark configuration for NH3-based capture processes is built upon the Chilled Ammonia Process, avoids the formation of solids and includes: (i) a multi-pressure desorber with recycled vapour compression that is able to decrease the high temperature steam requirements for solvent regeneration, i.e. at ca. 140–160 °C, to values as low as 1.1 MJthkgCO2captured−1, (ii) a vacuum integrated stripper for the recuperation of the solvent that is able to use low temperature steam instead, i.e. below 100 °C, and (iii) a flue gas water-wash column that is able to reduce the NH3 concentration in the CO2-depleted flue gas to values below 10 ppmv without the need of an acid-wash column before the stack.